How to create your own Obelisk Arena?

For this you need to create an ancient_obelisks/ancient_obelisks_obelisk datapack Note: I started using modid in folder names after bugs with other mods that used same folder names

You must create a json for your arena:

• copy an existing json from the mod jar
• edit rooms_folder to point to your structure nbts
• size means how big your structure is. A size of 1 means 2x2, so 4 structure blocks. The way it works is it checks for any structures with names 0_0, 0_1, 1_1, and 1_0. A size of 2 would go up to 2_2 etc, making it a 3x3, so 9 structure pieces.
• Structure files must be max 16x[height]x16, height can be maximum possible

The arena must have command blocks with these ids:

• obelisk_spawner (put 4 or so of these, this is where mobs will spawn)
• obelisk_reward (put 1, either in the middle of the room or some place you want the rewards to spawn, ideally the player should see it right away)
• teleport_back_block (so players can return home, or to their last teleport loc)

That's it, have fun creating custom obelisk arenas!